Oil cooler for engines



Jan. 5, 1943. w. R. RAMSAUR OIL COOLER FO ENGINES Filed 'April s, 1940 5 Sheets-Sheet 2 Nro/e, MSA 01e. I

WA f1@ (3@ 6/2 f n Bxl/f ATTORNEY Jam. 5, w43. vv. R.' RAMsAUR 2,307,300

OIL COOLER-FOR ENGINESv Filed April 30,/- 1940 s-,shets-snq1b 3.

'DIUL CULER FR lENGlIM l Walter lEt. Ramsaur, Los Angeles, Calif., assignor to 'lhe Garrett Corporation, Airesearch Manufacturing Company llllivision, llos Angeles, Calif., a corporation of California Application April 30, "1940, Serial No. 332,612

8 Claims.

My invention relates to improvement in oil coolers of the type used to cool the oil employed tor crank case lubrication in internal combustion engines.

Coolers ci this type are now being extensively employed with powerful internal combustion engines, such as used in transport and military aircraft, to minimize the disadvantages resulting from the decrease in viscosity and the deterioration of lubricating oil at high temperatures. As

the temperature of the oil is increased, the viscosity and lubricating value of the oil rapidly decreases. One authority advises that the rise in temperature of lubricating oil from 100 F. to

210 F. results in a decrease in the viscosity of the oil to approximately one-twelfth of its viscosity at 100 F. Lubricating oils are now considered internal coolants for engines. Excessively high' temperatures of the oil results in rapid deterioration of the oilat the elevated temperatures. Oil coolers are now in use with internal combustion engines, wherein the heated oil is brought into heat exchanging relation to a cooling medium by passing the oil into spaces or passages whioh lie in close relation to other spaces wherein the cooling medium, for example, air or in these oilV coolers, the oil passages are made .relatively narrow so that a large portion of the oil will be in contact with the walls of the passages, the result being that when the oil is cold vand consequently in viscous state. it either will not ow at all or will flow very slowly through the oil spaces or passages of the oil cooler. To

water, is circulated. To maintain high eiciency to be cooled is directed, and it is an object of th'e invention to make one or more of these baffles hollow and to provide means for by-passing oil through these hollow ballles, whereby the bypassed oil will be brought into effective heat exchanging relation to oil in the normal oil spaces or passages of the oil cooler.

It is an object of the invention to provide an oil cooler having a shell wherein baiiles or partition walls are employed to provide spaces to receive the oil which is to be cooled,and to employ within the shell in suitably spaced relation hollow partition walls which will form passages for a warm-up uid, thereby making it possible to electively distribute the passages for accommodation of the warm-up uid within the shell of the cooler with the result that the warm-up is efficiently accomplished.

It is an object of the invention to provide an oil cooler of the character set forth in the preceding paragraph having control means whereby the oil is directed through a by-pass when it is cold and is proportionately directed through oil cooling spaces of the oil cooler as the temperature gradually increases, until a condition is reached wherein the oil has been brought to maximum operating temperature, and at which time substantially all of the oil from the crank case of th'e engine may pass through the oil cooling spaces of the cooler.

A further object of the invention is to provide in an oil cooler a simpleiconstruction wherein partition walls are installed within the shell of relation to oil inthe oil cooling spaces oi the by-pass oil from theengine so that such oil will shell, and wherein an eiective distribution of the oil to be-cooled is obtained, thereby achieving high eiciency in the operation of the cooler.

Itis an object of the invention to increase the effectiveness of the thaw-out means by use of -a structure wherein the thaw-out chambers are relatively close together, wherein .back pressure is minimized by keeping the length of the thaw-out chambers within reasonable limits, and wherein the inlets and outlets of the cooling and thawout chambers are kept close together.

Further objects and advantages of the invention will be brought out in the following part of the specication.

Referring to the drawings which are for illustrative purposes only:

Fig. 1 is a plan view of a preferred embodiment of my invention.

Fig. 2 is a side elevation corresponding toFig.

l, a portion of this view being broken away to show underlying structure.

Fig. 3 is an end elevation of the cooler taken from the position of the arrow 3 of Fig. 2.

Fig. 4 is a cross-section on a plane represented by the line III- 6l of Fig. 2.

Fig. 5 is a cross-section taken on a plane indicated by the line 5-5 of Fig. 2.

Fig. 6 is a fragmentary section taken as indicated by the line 6 5 of Fig. 2.

Fig. l is an enlarged longitudinal section taken on a plane represented by the line 'Il-'I of Fig. 4, intermediate portions of this view being broken away to condense the View.

Fig. 8 is a view similar'to Fig. 7, but taken as indicated by the line Ill-2 of Fig. 4.

Fig. 9 is a fragmentary sectional View taken as indicated by the line 9--2 of Figs. 4 and 'l'.

Fig. l0 is a bottom perspective view of the oil outlet port tting employed in the oil cooler structure.

Fig. ll is an enlarged fragmentary section taken as indicated by the line lI-II of Fig. 2.

Fig. l2 is a diagrammatic view illustrating the unique positioning of the baffles and hollow baffles and the direction of flow of liquid through the oil cooler. Y

The oil cooler comprises a shell I I] of tubular form, and preferably consists of a cylinder made by bending a sheet of copper to form a tube, the meeting or overlapping ends of the sheet being joined as indicated at II in Figs. 4 and 5. For purpose of clarity, I have in Figs. 3 to 6, inclusive, indicated edge elevations of thin sheets by double lines and havel indicated sections of such sheets in heavy black lines, thereby making it possible to clearly distinguish openings through sheets from the adjacent portions of the sheets. For example, it will be noted that the edge of the shell I2 in Fig. 3 is in double lines, whereas in Fig. 4 the section of the shell IU is depicted by a heavy black line.

The oil to be cooled is introduced into the interior of the shell Iii, and while therein is brought into heat exchanging relation to a cooling means. In order that the oil to be cooled will be effectively distributed throughout the entire volume of the shell, partition walls or baffles I2 to Iii, inclusive, (see Figs. 3 and 4) are extended in planes running longitudinally within the shell Iii so as to divide the interior space of the shell into a plurality of spaces or passages I9 to 2li, inclusive, these spaces being elongated in a direction corresponding to the axis of the shell Ill and being interconnected in a manner which will be hereinafter described, so that an effective circulation of oil throughout all of these spaces may be obtained. Some of the partition walls or baffles, for example, the baffles I2 and I3, are of hollow construction for the purpose to l be later explained. Cooling means are extended in the oil spaces I9--2G so as to make heat absorbing contact with the oil therein. Such cooling means preferably consist of metal tubes open at the ends so that a cooling medium, such as air, may readily pass therethrough. For this purpose I preferably employ tubes 2l as best shown in Fig. 8. These tubes 2l are nearly as long as the shell Il). The intermediate portions thereof are circular in cross-section and the end portions 22 are expanded and are formed so as to be hexagonal in cross-section. These tubes 27! are placed in side-by-side relation so that the faces of the hexagonal ends 28 will be in cooperatlve engagement as shown at 29 in Fig. 3 to close the ends of the spaces I9--26, these hex` agonal ends 28 being joined to cach other and to other metal chambers of the assembly by use of solder, in accordance with the general practice of making cellular structures of radiator type.

The shell' Ill has near its right end as viewed in Figs. l and 2, and in the upper wall thereof as also shown in Figs. 4, 5 and 6, an oil inlet port 2t?, an oil outlet port 3l, a bypass inlet opening 32 and a bypass outlet opening 33, the openings 32 and 33 comprising longitudinally extending slots disposed substantially equidistant on opposite sides of the vertical medial plane A-A of the oil cooler. In the bottom wall of the shell I2, as shown in Fig. 5, there are secondary bypass ,openings .2li and 35 comprising narrow slots lying substantially in the vertical planes defined by the bypass openings 32 and 33. The partition wall or baille Ill is shown on the medial plane A-A, Fig. 4, comprising a sheet of metal, preferably copper or an alloy thereof, having at least the front and rear edges thereof bent in angular relation for cooperative engagement with the adjacent tube ends 28. In the preferred practice of the invention however, the wall Iii is bent along lines extending longitudinally thereof and in parallel relation, thereby forming adjacent sections 36 and 3l? lying at angles of 120, to correspond to the angularity of the external faces of.

the hexagonal end portions 28. The horizontal partition walls or baffles t5, I6, I'i, and I8, comprise metal sheets bent so as to provide horizontal sections or strips 38 connected by sloping sections or strips 39, Fig. 4, for cooperative engagementwith the hexagonal tube ends 28 as shown in Fig. 3. The hollow bales I2 and I3 are comprised of pairs of vertically disposed plates of the type described relative to the central partition wall It. Accordingly, I have shown the hollow baille .I 2 as comprising parallel metal walls Illa, and the hollow baiTle I3 as comprising spaced metal walls I b, these walls ILla and Iflb differing from the partition wall It in vertical dimension and in the provision of circulation openings between adjacent passages within the cooler. The walls I2, Illa, and Mb have flanges 42 along the upper and lower edges thereof for soldered connection with the shell Iii, and the edges of the partition walls I5, I6, Il, and I8 have anged portions along the edges thereof for connection to the parts engaged thereby. As shown in Figs. 3, 5, 7, and 9, front and rear ends of the spaces l2 and I2', Within the hollow ballles I2 and 2 are closed by vertically extending metal strips (Il and lill of zigzag form to correspond to the prole of the surfaces of the plates Illa and Mb respectively engaged thereby, these end strips lli and fil being soldered in place. The upper and lower extremities of the internal spaces I2' and I3 of the hollow bales I2 and I3 communicate with the upper and lower bypass openings 32, 32, and 25, as shown in Figs. 4 and 5. The lower portions of the spaces I2' and I3 are interconnected so that these spaces will be joined in a circulation passage for bypass uid. A feature of the invention is to provide means external of the shell I El to connect the lower extremities of the spaces I2 and I3. As best shown in Figs. 2, 4, and 5, I apply to 'the exterior face of the bottom wall of the shell Ill an arcuate pan 62 which cooperates with the shell I Il to form an arcuate vpassage i3 connecting the bypass openings 32 and 35 of the shell. This pan 132 has a bottom wallv ddl with peripheral walls or lips i5 extending upward into engagement with the shell I0. Under certain conditions of operation, as

will be hereinafter explained, abypass ow of oil will enter the inlet opening 32 as indicated by the arrow 45 of Fig. 5, will pass downward through the interior space I 2' of the hollow baille I2. 'Ihis oil will then flow across the interconnecting channel 43 and, enteringY the port 35 as indicated by arrow 41,` will pass upward through the interior space I3 of the hollow partition wall I3, and thence out through-the outlet bypass opening 33.

On the top of the shell I I provide an oil inlet space 48 which connects the inlet port 30 and the inlet opening 32 both with an inlet tting49 to which oil piping from a pump associated with the engine may be connected as indicated at 59. Also, on the top ofthe shell I provide an oil outlet space I providing connection with the outlet port 3|, this oil'outlet space being formed in part by an oil outlet port tting 52, a partition wall 53 having'the form shown in dotted lines in Fig. 1, and an outer arcuatewall 54 which extends also over the oil inlet space 48. As

' shown in Fig. 10, the outlet porttting 52 has a circular top wall 55 with an opening or port 58 therein. From the periphery of the wall 55 a cylindrical wall 51 extends downward, the rightward portion of the wall 51 having a semi-cylindrical skirt 58 extending downward as best shown in Figs. 4 and 10 to make engagement with the upper wall of the shell III, to serve as a partition wall between the oil outlet space 5I and a bypass outlet chamber 59 which communicates with the bypass outlet opening 33.- Adjacent the oil inlet tting 49', there is a port fitting 52a-which is similar in form to the tting 5 2 shown in Fig. 10, but is rotated on its axis through an angle of 180 so that, as shown in Fig. 6, the semicircular skirt 58a thereof will lie below the left- Ward portion of the -tting and an opening 6I will exist under'the rightward portion of the cylindrical wall 51a to connect the interior vof theiltting 52a with the bypass outlet chamber 59, formedin part by an arcuate wall 62 lying' -parallel to a portion of the shell IU- and an edge wall 63 which connects an edge of'thawall $2` with the shell I0. The members 42, 54, and 62 are of the same axial length, and on the exterior ing the front endsof the spaces 20 and 2|'. v'I'he rear ends of spaces 2I and 22am connected by an opening 11 in the lower part ofv the central partition wall I4, as shown in Fig. 5. e front ends of the spaces or passages 22 and 23 are connected by an' opening 18, Figs. 4 and 7, which passes through the lower portion of the hollow bailie-I3.` 'I'he rear end of passage 23 is connected to the rear end of passage 24'byan' opening 19 through the rear end portion of the horizontal wall I8. In the upper, forward portion of the hollow baille. I3 there is an opening 80 which connects the front end of the passage 24 with the front end of the passage 25. The rear end of passage 25 connects through an opening` 8| in the upper part of the central wall I4 with the rear end of passage 26, and'therefrom'the oil will flow forwardly in the passage 26,-to the outlet port 3| and thence Vthrough the oil outlet port 61 of the tting 66. The openings 16,A 18

and 80 respectively through the lower front por" tions of the hollow bailies I2 and I 3.are formed in the manner shown in -Figfl wherein openings` 18 and 80 are shown. Referring in particular to the opening 18, the plates I4b are cutas shown in Fig. 9 to outline the opening 18 and vertical` and horizontal portal mem'bers 82 and 83 arev solderedv between the edges ofthe -plates I4b. which form the opening.

'Ihe horizontal or upper portal member 83 is of such'1engththat'- it will extend from the upper endA of the member 82 to the zigzag strip 4I which closes the front end of the space I3' within the hollow baille I3.

' The opening 16 is formed from similar portal and 83h placed in inverted relation to the memof the shell IIJ between the edges of the members 42, 54, and 62 arcuate strips 64 and B5 are secured in the position Vof radially .extending anges, to reinforcetheshell I Il. Y'

To the port ttings 52 and 52a,'-as best shown in Fig.' 2,. an 'outlet iitting 66 is secured, this Yfitting 66 having an oil outlet port 6.1 and abypass outlet port 68, respectively connected to the chambers 5I and 59.4 The bypass outlet port B8 has in association therewith a control valve 69' with means 10 for moving it between opened vand closed relation to the port 68.' This means-10 is shown as a thermostatic elementA secured in downwardly projecting relation to a threaded plug 1I whicl'ris secured in the tting 6B above lthe port 68. Ihe thermostatic element 10 is so formed that as the temperature thereof increases the valve member 69 is moved downward toward the port B8 so as torestrict or prevent ow through this port 68. The tting 66 has an outlet 12'to which oil return 'piping 13 may bev connected, and within the tting 66 there is a'bailie 'I4 for directing oil from :the port 61 into engagement with the thermostat element 10.

In Figs. 2 and 4, it will be noted that the inlet port 30 for oil to be cooled is at the right or forward end of the shell and leads into the forward one passage to the other. It will be noted trom' this view that the hollow bales cooperat'eywithf the other baiiies in order to divide the space rin the shell into a series of vinterconnected passages.

'Ihese interconnected passages are joined izogether through openings formedin' the hollow baies and in the other bailies, as is clearly shown in the 4various views.' particularly Fig. 12'; ".'By

reason of thearrangement of the hollow b aiilesV it will be seen that the oil to be cooled will 'flow along one side of a hollow baille. It willtliow` through the opening inthe hollowbale' andlinay then ow along the other side of 'the' hollow baille. When the device has become clogge'dfand' hot oil is delivered through the thawfoutjmeans, it will be seen thatevery. chamber within the voil .cooler has at least one wall throughwhic'h itmay Y derive heat from a thaw-out passage. It will further be seen that the o il passes along one side of the baille and then' along the other sideof the v I baille, thus obtaining a maximum heat transferring eiciency and thus not only accomplishing a thawing out of'the oil cooler, but insuring a substantial velocity ow through the oil cooler,- and thus assuring a. more rapid return to normal operation.' I

VAs shown in Figs.. 2 and 1l myinvention'provides a simple means Vfor simultaneously draini ing the oil from the oil cooling spacesandthe'- end of the passage |91 In the wall I5 between and 3l. l

warm up, heatwill bef transmitted through` the i bypass spaces of the oil cooler. The central portion of the pan 42 .is deformed so as to provide a :dat wall portion 84 `to which a flange 8 5 `may' be secured, this flange,l 85 having a threaded erably coaxial therewith; A plug-,90 is provided to simultaneously `close @the opening 81 'and' likewise obstruct oriclose the lower end ofthe dis-V I charge tube 89 which leads'downward from the bottom wall of theshell l0.' This `plug has aA recess QI inthe inner facethereof which recelves` the lower portion of the discharge tube 89. The

connected in such mannerfthat hey will all drain down` through the passages. 2l and v2 2 `when the plugdsis removed, and at the same timeoil. in

the interior spaces of theihollow baiiles `I2 and the ollowing description.l It willjbe perceived that the oil inlet fitting is a.t` all times connectedr throughthe chamber 48 with the partiti-and with the `bypass inlet opening 32. .Alsoptheoute let port 3l is at all times in open communication with theoumet manges.' "whether ou may now throughthe bypass passages |2', 43 and I3'vwil1 depend entirely upon the position of the valve 1 member 69. `Wherethe control means for the valve 69 comprises a thermostat, the valve will be in open position, as shown in Fig. 2, when `the engine has been stopped fora long enoughperiod of time to permit the foil` in the oil circulating system to cool. Accordingly, when the engine'is started after a period oi'` inoperation', the cold oil pumped, from the crank'case ofth'e engineumay pass through the bypass passages of the oil cooler. rAt this time there may be a small or sluggish ow of oil through the oil `cooling spaces of the cooler as the result-in the diierential inA pressure between [the4 inlet and youtlet ports 30 As the oil from the engine starts to walls Ma and I'4b of the bypass passages to warm the4 oil in the adjacent oil `cooling spaces ofthe device, and as the increase inthe oil temperaturey continues there will be a `further transfer of heat into the oil in the oil coolingfspaces of the device I and also. a gradual closing ofthe valve` 69 due to the rise in temperature towhich" the thermostat-, element 'l0 is subjected,V untilv a condition finally reached wherein the valve memberGQ s ub'4 stantially closes theportf, thereby closing the outlet'endof theoil bypass so that substantially`- the engine, will pass .the entire ilow of oil from throughthe oilv coolingspaces. y I claim as'my invention.: r f

1. In an oil c oolerof-` the character described, `the combination of; 4a shell having tubes extendingftherethroughkthus providing a space laround said tubes through which liquid to-be `cooled may be circulated, `said shell having an inlet port and anfoutlet'vport connectedtogsaid'space; baiiies V in said 'shell dividingsaid space into a pluralityV f of passages connected in series, the .rst of which is 'connected to safidfinlet port and 'the last yof f which is connected tov said outlet port, at least one of said baffles being a hollow baille and including a pair vof` spaced wallswhich form` ab .Y thaw-out passa'ge`,`oney endof-` which is connected y to said inlet port and th-other end of which is connected to said outlet` port,l said' hollowl batlle` .40' ing therethrough, thus providingpa'spac being so arranged that one passage ison one `side thereof and another? passageison' thezother side thereof, there being aV connecting:` ope through said hollow' baffle" so *that* the *l 5 be cooled may ilowfrst "alongone sid o hollow bale and theri alongljthezo lier` `d said hollow baille; and mea trolling l l fioweof -liquid through said thaw-outfp 2.- In` an oil` cooler of the character l0 thecombination of': a shellhaving" ubes i ingtherethrough, thu'sprovidng said tubes throughlwhich liquid to be circulated,` said shell having; an inlet 'ort e an outlet port connectedto sa 15 said shell dividing said spacefin A-oil cooling spaces I9 vto 26, `in lusive, are inter- Q inlet port andoneend of theY of`the other of said hollow balli to said outlet port, `"each i of `sai said hollow baiiles and thenfal gt ,Y 'of theothei yof said hollow bailles and mr controlling fthe-flow-` of` liquid throg 'thaw-out passage. f V3.Y In an oil `c 'olerof `thecharacter.desc bed,` the combination of: ashell having tubes, exten 0 said tubes through which lquidtorbe coo e may be circulated, said/shell havi d. an outlet port connected to (s said shell dividing said space'fin` passages connectedlin series, the] 1 1 is connected to 'said inlet port 'and'ythe` las of "which is jconnectedto saidoutletyporaatfl two of said baffles constituting hollowbaflles, each of' which includes a pair of spaced; walls -wliiil .50 form a thaw-outpassa'ge, onefend of` one hollow bailles being connectedto saidinlet 'and the adjacent end of the other of saidv baiiles beingconnectedA to said`outlet port, wall` means applied` externallyxtooneside of said s "11g and providing an; interconnectingthawwut p sag'e connected to a. "1 jacent ends of said hollow` "bailles iniiaQ x"nannerI toconnecttheytha`w ut r passages` thereof, Vin series; 'and means for c n i trolling the iiow of liquid through` said. Passages. A f -l s f4. In an oil cooler of the character",described,` thccembination of a shell having tubesextend-` ing therethrough, `thus providing a spacearoiind said tubes through which liquid tofbe` cooledmay` ybe circulated; inlet fand outlet means at oneside of said shell for conductingliquidgthroughithe space within said shell; aj pair. of `hollowba'ines extending in spaced relation -throughnthe interior"l of. Vsaid shel1 fror n said'side therofwheiezsaid ,.0 4inlet and outlet means' are located to the opposite sidethereOf. said hollow baflies dividing jsaidlspac'e in said shellinto apluralitypf seriesconncted passages', the outer-facesof s aidlhollowzsbames being exposed `toat least a partlof `wallmeansat is 1 connecting the interiors of said hollow haines together, thus connecting them in series; and means at said iirst side of said shell for placing both the inlet and outlet means in open communication with the interiors of said hollow bames so that liquid may pass directly therethrough in heat exchanging relation to said passages and in multiple ilow relation with the iiow through said passages.

5. In an oilcooler of the character described, the combination of a shell having heat exchange means therein and having inlet and outlet pas- V sage means communicating with the interior of the shell; wall means within said shell for defining oil passages whereby the oil to be cooled will be carried back and forth in said shell in heat exchanging relation to said heat exchange means from said inlet passage means to said outlet passage means, said wall means comprising at least one hollow bame having inlet and outlet ports connecting its interior with said inlet and outlet passage means and thereby providing a thaw-out passage within said shell, said hollow bade being so positioned relative to the path of ow of oil in said shell that oil to be cooled will flow rst across one side of said hollow bame and then across the other side of said hollow baiiie; and means for controlling a now of liquid from said inlet passage means through said thaw-out passage to said outlet passage means. l

6. In an oil cooler of the character described,

the combination of: a shell having heat exchange means therein and having inlet andoutlet passage means communicating with the interior oi' the shell; wall means within said shell for dening oil passages whereby the oil to be cooled will-be carried back and forth in saidI shell in heat exchanging relation tc said heat exchange means from said inlet passage means to said outlet passage means, said wall means comprising a plurality of hollow bames placed within said shell so that a side face of one of said hollow haes will be adjacent to and spaced from the side face of another of said hollow baes, the interiors of which are connected to said inlet and outlet passage means so as to form thaw-out passages, said hollow baies being so positioned in said shell that oil to be cooled will dow within said shell first across one side and then across the other side of each of said hollow bames; and means for controlling a flow of oil through said thaw-out passages from said inlet passage means t0 said outlet passage means.

7. In an oil cooler having a shell, heat transfer means in the shell, an oil inlet port and an oil outlet port communicating with the interior of said shell; spaced walls forming a hollow bame disposed in said shell to define passage means for a iiow of oil Within said shell from said inlet port to 'said outlet port, the interior space of said hollow baule being isolated from the iiow of oil in said passage means defined within said shell, the interior space of said hollow baie comprising a thaw-out passage and said hollow baffle being positioned so that both sides thereof will be exposed to oil within said shell, and saidhollow bame having a transverse port extending from one side to the other thereof and through both of said spaced walls for transfer of the oil to be cooled from one part to another of said passage means; and means for directing a flow of thawout fluid through said thaw-out passage of said hollow baiile, said thaw-out iiuid being other than the oil flowing through said passage means.

8. In an oil cooler of the class described, the combination of: a shell having inlet and outlet means communicating with the interior thereof and having a heat absorbing means therein; bae means within said shell for guiding the oil to be cooled from said inlet to said outlet means, at least one of said baille means comprising a hollow wall projecting from one bounding wall oi said shell into the interior space of said shell and toward another bounding wall of said shell, said hollow wall being so formed that it provides a passage within said shall in transverse relation to said hollow wall through which the oil to be cooled may iiow from the interior space of said shell adjacent one face of said hollow wall to the space within said shell adjacent the opposite face of said hollow wall; and means for passing a controlled ow of warm-up uid through the 

